A 59-year-old woman was arrested in Fukuoka on Thursday for allegedly stabbing her father and mother to death at their home, local police said.
The three lived in the same residence.
The woman is suspected of stabbing her parents, Masaru Oda, 89, and Roko Oda, 82, at their shared apartment. The two were pronounced dead at the scene.
Her husband, who also lived with them, was out at the time and received a call around 1 a.m. from his wife who said she had killed her parents. He returned home to find them on the floor bleeding from the chest and contacted the authorities.
A kitchen knife covered in blood was discovered in the apartment, police said.
When investigators arrived, the woman was in a stupor and did not respond to their inquiries. She is currently in a hospital and is thought to have overdosed on medicine.
Police said the suspect may be suffering from schizophrenia and her name will be withheld until a psychiatric evaluation can be made.